H-SIMO: A Hybrid Single-Inductor Multi-Output 5-Level Thin-Oxide Power Management Unit Achieving 91.4% Efficiency from Li-ion Battery Voltages in 28nm FD-SOI

This paper presents a miniaturized Li-ion-compatible 5-level hybrid single-inductor multi-output (H-SIMO) power management unit (PMU) in 28nm FD-SOI for powering IoT devices. Miniaturization is achieved by combining the benefits of SIMO converters with the benefits of hybrid multi-level converters. The PMU is implemented in 28nm FD-SOI in an arrangement that naturally exploits the required transistor stacking of a 5-level converter to enable full coverage of the 2.8-4.2V Li-ion battery voltage range using only 1V thin-oxide transistors. The 0.42mm ² die independently regulates three different outputs over 0.4-0.9V from 10μW to 40mW using a single 1.28mm ³ inductor with 91.4% peak efficiency.